# CCL: SCF convergence problem with M06L functional in Gaussian 09

*From*: "Bulumoni Kalita"
<bulumoni:-:dibru.ac.in>
*Subject*: CCL: SCF convergence problem with M06L functional in
Gaussian 09
*Date*: Tue, 1 Mar 2016 01:58:35 -0500

Sent to CCL by: "Bulumoni Kalita" [bulumoni(~)dibru.ac.in]
Dear Users,
My observations regarding the Pd4 calculations:
1) In my job input, it was by mistake um06l. But for such a system
(multiplicity=1), restricted and unrestricted calculations give the same
results.
2) It completes very fast (27 SCF cycles) with b3lyp as said by Robert Molt.
But with m06l, it takes long time (exceptionally long). Here, one SCF Done
takes 129 cycles and the other ~30. And the calculations keeps on oscillating
between these two values for quite long time. Moreover, for higher
multiplicities, normally calculations are more time consuming.
Now, I understand that for the above different situations, the initial guesses
may be very different. But, how to check and confirm that the initial guess is
not too far from the expected one so that the SCF calculations take less number
of cycles as well as the calculation for such a small molecules completes
successfully soon.